Electric motor and brake.



' H. A. BALOOME. ELECTRIC MOTOR AND BRAKE.

APPLICATION FILED JAN. 28, 1905.

1,060,966. I v Patented May 6,1913.

UNITED STAT-Es PATENT OFFICE.

HERBERT L BAIiCOME, OF BOSTON, MASSACHUSETTS, ASSIQNOR TO B. F. STURTEVANT COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

ELECTRIC Moron AND BRAKE. I

To all whom it may concern:

Be it known that I, HERBERT A. BAL- ooME, .a citizen of the United States, residing at Jamaica Plain, Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improve ments in Electric Motors and Brakes; and I do hereby declare the following to be a full, clear, and exact descri tion of the invention, such as will enable ot ers skilled in the art to which it appertains to make and use the same.

The present invention relates to an improvement in electric motors and brakes.

The object of the invention is to improve the construction of electric motors provided with automatic electrically released brakes.

The invention consists in the electric 1110- tor and brake hereinafter described and particularly defined in the claims.

In the accompanying drawings Figure 1 is a side elevation of the preferred embodiment of the invention, of which the upper half is in section, and Fig. 2 is an end elevation with the brake cover removed.

The motor casing 1 is rovided with heads 2 and 3 which carr t e bearings for th'e' armature shaft 4. he brake mechanism is located outside of the casing of the motor and in convenient position for access thereto for examination or repair. The brake mechanism consists of a brake disk 5 which is provided with a sleeve 6 splined to 'the armature shaft 4 whereby the sleeve. 6 may slide longitudinally upon the shaft but is held from rotative movement with relation theref to. A cylindrical extension 7| from the outer which is secured by screws 12 to the-casing 3,

the projections 13 of the brake shoe holder engaging the ends of the brake shoes -1O and thereby holding them from rotative move ment. The brake disks and brake shoe holder are made of brass or some other nonmagnetic material. Two pole pieces are Specification of Iictters Patent.

' Application filed January 28,1905. Serial No.242,994. 1

fprovided the faces of which correspond to the inner surfaces of the brake-shoes and which whenv energized attract the brake Patented May 6, 1913.

shoes and hold them in the position shown .in Fig. 1, springs being provided to force them outward when the magnet is deenergized. The I pole piece 14 is cruciform in general shape and secured by screws 15' to the casing .The other pole-piece constitutes a portion of the'casin 3 indicated at- 16. For each brake shoe our springs 17 are provided which are received in cavities 1n the pole pieces, two 1n each. A recessgl's provided in the casing 3 in which the brake coil 18 is placed. The brake coil 18 is connected either in series or in shunt with the motor circuit and when energized by the passage of the current therethrough the pole piece 16 of cast iron and the pole piece 14,

referably of soft steel, are energized therey and attract the brake shoes and hold faces of the brake disks 5 and 8. When the current is discontinued in the "coil 18 the brake magnet is denergized and the springs 17 force the brake shoes 10 outwardly into engagement ,w1th the brake surfaces of the" brake 5 and 8, and inasmuch as the brake shoe holder 11 holds the brake shoes from rotative movement they thereby apply a heavy braking to the armature shaft.

them out of engagement with the brake surcover 19 of sheet metal is secured by bolts 20 to the casing 3. The compactness of this construction, itsv accessibility and the efii-' ciency of the mode of application of the brake are such as to commend it.

It will be observed that the brake'mechanismoccupies but a small space, and being supported upon the head of the motor case ing involves the addition of but few parts to the motor. The brake mechanism taken as a whole is very light considering the effective brakingpower, and the construction by virtue of which the weight of the brake magnet is supported by the head instead of by the shaft is also a matter of importance. The radial movement of the brake shoes in the application of the'brake is another feature which contributes to the utility of the construction, as also'the inclining of the surfaces, whereby a wedging action is secured; It is also to be noted that the application of the brake has no tendency to move the armature shaft endwise in its bearings and that as a consequence thrust bearings for the able brake members, an electro-magnet for armature shaft may be dispensed, with. Owing to the placing of the brake upon the outside of the motor case the heat resulting from the application of the brakes is more readily radiated than in prior constructions in which the brake mechanism is inclosed within the motor case. Another feature of this construction resides in the removability ofthe entire brake mechanism without dismantling the motor.

Having thus described the invention,wha t is claimed is 1. A brake for an electric motor having a shaft, having, .in combination, axially balanced disks mounted to move'longit-udinally uponthe motor shaft, radially movholding said brake members from, and

-means for forcing them into contact withs aid brake disks, and means for holding the brake members from rotative .movement,

substantially as described. I

2. Asbrake for an electric motor having a shaft, having, in combination, friction disks mounted to slide longitudinally upon the motor shaft, radially movable brake members adapted, when moved radially, to engage and apply braking force to said disks,

a spider for holding said brake members from rotative movement, an electro-mag-net for holding the brake members from --engagement with the friction disks, and

, net for withdrawing them from engagement therewith, substantially as described.

4. An electrically released brake for an electric motor which has a shaft and ajcastion member mounted on the shaft, a radiallymovable brake shoe mounted on the casing for engaging the rotatable friction member, 'a magnet winding in a recess formed in the outer face of the end of the casing, a pole face on the end of thelcasing facing radially outward, a pole plate soing and having a pole face facing radially outward and cooperating with the pole face of the casing to hold the brake shoe from engagement with the rotatable friction member, and a spring'for forcing the brake shoe into engagement with the rotatable friction member, substantially as described.

5. ,An electrically released brake for an electric motor which has a shaft and a casing, having, in combination, a rotatable friction member mounted on the shaft, a radially movable brake shoe for engagingthe rotatable friction member, a polepiece secured to the end of the motor' casing, a magnet having pole faces facing radially outward for holding the brake shoe from en HERBERT A. BALooME.

WVitnesses HORACE VAN EVEREN,

FRED O. FISH.

ing, having, in combination, a rotatable friccured to the end of the casing over the windgagement with the rotatable friction mem- 

